variety of tubes

Guest · Post by **Guest** » Sun Jan 30, 2005 9:37 am

what would be the best way to get a superlead to bias correctly for a variety of tubes/ el34 6550 kt666 etc.

thanks

Flames1950 · Post by **Flames1950** » Sun Jan 30, 2005 8:01 pm

You'd have to rig a switch to change the value of the bias resistor that's in-line with the bias adjustment pot.
You'd probably need to put a 100K in-line on the board (I'm guessing that based on the resistor it took to bias KT66 tubes on my amp) and use a switch to add another 100K in parallel to the first, lowering the resistance value to 50K (close to the 47K that EL34's take in my amps.)
Those values were for a fifty watt, BTW. You may need to make some adjustments based on what your Super Lead resistor value is currently.